1,4-Butanediol (hereinafter, sometimes simply referred to as “1,4BG”) is a very useful substance used as a raw material of various solvents or derivatives.
Conventionally, a variety of methods for industrially producing 1,4BG by using petroleum or other fossil fuels as a raw material are known. For example, there are a method where diacetoxybutene is obtained as an intermediate by an acetoxylation reaction using acetic acid and oxygen and using butadiene as a raw material and the diacetoxybutene is hydrogenated and hydrolyzed to produce 1,4BG; a method where maleic acid, succinic acid, maleic anhydride and/or fumaric acid are used as raw materials and these materials are hydrogenated to obtain a 1,4BG-containing crude hydrogenation product; and a method where butynediol obtained using acetylene as a raw material by contacting it with an aqueous formaldehyde solution is hydrogenated to produce 1,4BG.
Recently, a method for producing a biomass-derived 1,4BG by using a biomass resource as a raw material has also been developed, in addition to the conventional method of producing 1,4BG by using petroleum or other fossil fuels as a raw material. For example, there are a method where succinic acid obtained by the fermentation of a sugar is hydrogenated to obtain 1,4BG (Patent Document 1), and a method where 1,4BG is directly obtained by fermenting a biomass resource such as sugar (Patent Document 2).
When a product comparable to a petrochemical product produced from a fossil fuel such as petroleum is produced from a biomass resource, a refining process on an industrial scale (large-scale process) is necessary for stably maintaining the production volume or quality. For example, in the case where the biomass resource used as a raw material is a sugar or the like, the target product is obtained by the fermentation thereof with bacteria, but for maintaining the quality equivalent to that of a product obtained by the conventional production process using a fossil fuel such as petroleum, a refinement technique capable of highly removing impurities contained in the raw material or various byproducts generated in the course of fermentation is required.
As an example of such a refinement technique, a refinement method regarding biomass-derived 1,3-propanediol is described in Patent Document 3.
Also, as a method for refining biomass-derived 1,4BG, a general refinement method is described in Patent Document 4.